Control Screen Assembly

ABSTRACT

Screen assemblies capable of being disposed in a bore for hydrocarbon fluid production are described. The screen assemblies can support filter mediums and reduce or eliminate plugging by swellable material. One screen assembly includes filter mediums supported by a rigid member located exterior to a portion of a base pipe. The rigid member can include openings through which the filter mediums can be in fluid communication with an inner diameter of the base pipe. Swellable material can be disposed exterior to a second portion of the base pipe adjacent to the rigid member. The filter mediums can be displaced to contact a wellbore and the rigid members can help reduce or prevent plugging of screen assembly openings.

TECHNICAL FIELD OF THE INVENTION

The present invention relates generally to control screens forsubterranean fluid production and, more particularly (although notnecessarily exclusively), to a control screen assembly having a rigidmember that includes an opening providing fluid communication between afilter medium and an internal flow path of a base pipe.

BACKGROUND

Hydrocarbons can be produced through a wellbore traversing asubterranean formation. In some cases, the formation may beunconsolidated or loosely consolidated. Particulate materials, such assand, from these types of formations may be produced together with thehydrocarbons. Production of particulate materials presents numerousproblems. Examples of problems include particulate materials beingproduced at the surface, causing abrasive wear to components within aproduction assembly, partially or fully clogging a production interval,and causing damage to production assemblies by collapsing onto part orall of the production assemblies.

Gravel packing the well adjacent to the production interval can assistin stabilizing the formation surrounding the production interval and infiltering particulate materials before the particulate materials enterthe production pipe. Gravel packing can include lowering a sand controlscreen into the wellbore on a work string to a position proximate aselected production interval. A fluid slurry, including a liquid carrierand a material such as gravel, is pumped down the work string and intothe well annulus formed between the sand control screen and a perforatedwell casing or open hole production zone. The gravel is deposited in thewell annulus to form a gravel pack. The gravel pack is highly permeableto hydrocarbon fluids, but can block particulate material carried in thehydrocarbon fluids. The gravel pack and sand control screen can alsostabilize the formation surrounding the production interval to preventformation collapses.

Complete gravel packing at a selected production interval can bedifficult to achieve due to the formation of sand bridges and othercomplications experienced when pumping the fluid slurry down the workstring. Expandable sand control screens can be used in place of gravelpacks that may be less problematic to locate in the wellbore and mayprovide similar filtering and formation stability as gravel packs.

One expandable sand control screen is a control screen assembly thatincludes a swellable material, such as a high-swelling rubber, and afilter device on the exterior of the swellable material. The swellablematerial can be located proximate the production interval and, whenactivated by a fluid, expand to displace the filter device to thewellbore. The assembly includes openings through which hydrocarbonfluids are directed by the filter device into a base pipe. A telescopingpiston can be located in the opening and can support the filter deviceas the swellable material expands. This type of expandable sand controlscreen can be effective in filtering and providing formation stability.

In some applications, however, the swellable material may swell into theopenings or otherwise swell to block, partially or completely, fluidcommunication between the interior and exterior of a base pipe. Blockingfluid communication may result in the swellable material partially orcompletely plugging the opening to the base pipe. A rework of thecontrol screen assembly may be required to alleviate the plugging.Reworks cost substantial time and money because they require suspensionof hydrocarbon production for a measurable amount of time and requireduplication of work in locating the control screen assembly in thewellbore.

Therefore, screen assemblies that can provide radial support toformations and reduce or eliminate plugging are desirable. Screenassemblies that eliminate or reduce reworks are desirable.

SUMMARY

Certain embodiments of the present invention are directed to screenassemblies that can filter particulate materials in hydrocarbon fluidsfrom a hydrocarbon-bearing subterranean formation and reduce oreliminate plugging. Reducing or eliminating plugging can reduce oreliminate a need for reworks. The screen assemblies may include aswellable material without requiring an opening to be created in theswellable material. Certain screen assemblies can provide stability to awellbore traversing a subterranean formation.

In one aspect, a screen assembly that can be disposed in a bore isprovided. The screen assembly includes a base pipe, a rigid member, aswellable material, and a filter medium. The base pipe includes asidewall portion with an opening. The rigid member is disposed exteriorto a first portion of the base pipe. The rigid member includes anopening in fluid communication with the opening of the base pipe. Theswellable material is disposed exterior to a second portion of the basepipe. The filter medium is at least partially disposed exterior to theswellable material and is in fluid communication with the opening of therigid member. In response to contact with an activating fluid, theswellable material can expand and displace at least part of the filtermedium toward a surface of the bore.

In at least one embodiment, the screen assembly includes a pistondisposed in the opening of the rigid member and coupled to the basepipe. The piston includes a telescoping portion coupled to the filtermedium. The telescoping portion can radially extend from the opening ofthe rigid member when the swellable material expands. The filter mediumcan filter fluids and direct the fluids to an internal flow path of thebase pipe through the piston.

In at least one embodiment, the screen assembly includes a materialbetween the filter medium and the rigid member. The material includes atleast one of a non-swelling media or a low-swelling media. The materialcan provide a temporary seal between the filter medium and the rigidmember. In some embodiments, the material includes rubber.

In at least one embodiment, the activating fluid to which the swellablematerial is responsive includes at least one of a hydrocarbon fluid,water, or a gas.

In at least one embodiment, the filter medium has a cross-sectionalshape of at least one of a kidney shape, an oval, a circle, or arectangle.

In at least one embodiment, the rigid member is a ring that is at leastone of a metal, a composite polymer, or a non-swelling rubber compound.

In another aspect, a screen assembly that can be disposed in a bore isprovided. The screen assembly includes a base pipe, a rigid member, aswellable material, and a plurality of filter mediums. The base pipeincludes a sidewall portion that has a plurality of openings. The rigidmember is disposed exterior to a first portion of the base pipe andincludes a plurality of openings. Each opening of the plurality ofopenings of the rigid member is in fluid communication with an openingof the plurality of openings of the sidewall portion. The swellablematerial is disposed exterior to a second portion of the base pipe. Theplurality of filter mediums are at least partially disposed exterior tothe swellable material. Each of the plurality of filter mediums is influid communication with at least one of the plurality of openings ofthe rigid member. In response to contact with an activating fluid, theswellable material can expand and displace at least part of each of theplurality of filter mediums toward a surface of the bore.

In another aspect, a screen assembly that can be disposed in a bore isprovided. The screen assembly includes a base pipe, a first rigidmember, a second rigid member, a swellable material, and a plurality offilter mediums. The base pipe includes a sidewall portion with a firstplurality of openings and a second plurality of openings. The firstplurality of openings are located at a first portion of the base pipe.The second plurality of openings are located at a second portion of thebase pipe. The first rigid member is disposed exterior to the firstportion of the base pipe. The second rigid member is disposed exteriorto the second portion of the base pipe. The swellable material isdisposed exterior to a third portion of the base pipe. The plurality offilter mediums are at least partially disposed exterior to the swellablematerial. Each of the plurality of filter mediums is in fluidcommunication with at least one opening of the first plurality ofopenings or the second plurality of openings. In response to contactwith an activating fluid, the swellable material can expand and displaceat least part of each of the plurality of filter mediums toward asurface of the bore.

In at least one embodiment, the third portion of the base pipe islocated between the first portion and the second portion.

In at least one embodiment, each of the plurality of filter mediums isin fluid communication with at least one opening of the first pluralityof openings or the second plurality of openings through at least one ofa plurality of openings of the first rigid member or the second rigidmember.

In at least one embodiment, each of the first rigid member and thesecond rigid member includes a first receiving portion and a secondreceiving portion. The first receiving portion can support a firstfilter medium of the plurality of filter mediums in a runningconfiguration. The second receiving portion can support a second filtermedium of the plurality of filter mediums in the running configuration.In some embodiments, the first receiving portion and the secondreceiving portion define grooves for supporting the first filter mediumand the second filter medium of the plurality of filter mediums in therunning configuration. In some embodiments, the second rigid member isrotated forty-five degrees relative to the first rigid member and thefirst receiving portion of the first rigid member is aligned with thesecond receiving portion of the second rigid member.

These illustrative aspects and embodiments are mentioned not to limit ordefine the invention, but to provide examples to aid understanding ofthe inventive concepts disclosed in this application. Other aspects,advantages, and features of the present invention will become apparentafter review of the entire application.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic illustration of a well system having screenassemblies in a running configuration according to one embodiment of thepresent invention.

FIG. 1B is a schematic illustration of a well system having screenassemblies in an operating configuration according to one embodiment ofthe present invention.

FIG. 2 is a side view of a screen assembly of FIG. 1A in a runningconfiguration according to one embodiment of the present invention.

FIG. 3 is a side view of a section of the screen assembly of FIG. 2 in arunning configuration.

FIG. 4A is a cross sectional view along line 4A-4A of a screen assemblyof FIG. 1A in a running configuration according to one embodiment of thepresent invention.

FIG. 4B is a cross sectional view along line 4B-4B of a screen assemblyof FIG. 1B in an operating configuration according to one embodiment ofthe present invention.

FIG. 5A is a cross sectional view along line 5A-5A of the screenassembly of FIG. 1A in a running configuration according to oneembodiment of the present invention.

FIG. 5B is a cross sectional view along line 5B-5B of the screenassembly of FIG. 1B in an operating configuration according to oneembodiment of the present invention.

FIG. 6A is a cross sectional view of a screen assembly in a runningconfiguration according to one embodiment of the present invention.

FIG. 6B is a cross sectional view of a screen assembly in an operatingconfiguration according to one embodiment of the present invention.

FIG. 7A is a cross sectional view of a second embodiment of a screenassembly in a running configuration according to one embodiment of thepresent invention.

FIG. 7B is a cross sectional view of the second embodiment of the screenassembly of FIG. 7A in an operating configuration according to oneembodiment of the present invention.

FIG. 8 is a side view of a rigid member capable of being included in ascreen assembly according to one embodiment of the present invention.

FIG. 9 is a cross section view along line 9-9 of the rigid member ofFIG. 8 according to one embodiment of the present invention.

DETAILED DESCRIPTION

Certain aspects and embodiments of the present invention relate toscreen assemblies capable of being disposed in a bore, such as awellbore, of a subterranean formation for use in producing hydrocarbonfluids from the formation. The screen assemblies may be configured tosupport filter mediums and reduce or eliminate plugging by swellablematerial. A screen assembly according to some embodiments includesfilter mediums supported by a rigid member located exterior to part of abase pipe. The rigid member can include openings through which thefilter mediums can be in fluid communication with an inner diameter ofthe base pipe. Swellable material can be disposed exterior to a secondpart of the base pipe and adjacent to the rigid member. The filtermediums can be displaced by the swellable material to contact a wall ofthe bore and the rigid members can help reduce or prevent plugging ofscreen assembly openings. In some embodiments, the screen assembly is asand control screen assembly that can reduce or prevent production ofparticulate materials from a well that traverses a hydrocarbon bearingsubterranean formation or operates as an injection well.

FIG. 1A shows a well system 10 with screen assemblies according tocertain embodiments of the present invention. The well system 10includes a bore that is a wellbore 12 that extends through various earthstrata. The wellbore 12 has a substantially vertical section 14 and asubstantially horizontal section 18. The substantially vertical section14 includes a casing string 16 cemented at an upper portion of thesubstantially vertical section 14. The substantially horizontal section18 is open hole and extends through a hydrocarbon bearing subterraneanformation 20.

A tubing string 22 extends from the surface within wellbore 12. Thetubing string 22 can provide a conduit for formation fluids to travelfrom the substantially horizontal section 18 to the surface. Screenassemblies 24, 26 are positioned with the tubing string 22 in thesubstantially horizontal section 18. The screen assemblies 24, 26 areshown in a running or unextended configuration. In some embodiments,screen assemblies 24, 26 are sand control screen assemblies that canfilter particulate materials from hydrocarbon fluids, direct thehydrocarbon fluids to an inner diameter of the tubing string 22, andstabilize the formation 20.

FIG. 1B shows the well system 10 with screen assemblies 24, 26 in anoperating or a radially expanded configuration. Each of the screenassemblies 24, 26 can include a base pipe, a rigid member, swellablematerial, and filter mediums. The rigid member may be a ring made from ametal, composite polymer, non-swelling rubber compound, or the like andmay be disposed exterior to part of the base pipe. Examples of metalsfrom which the rigid member may be made include steel, iron, brass,copper, bronze, tungsten, titanium, cobalt, nickel, and a combination ofthese or other types of materials. The swellable material may be arelatively high swelling rubber or polymer and may be disposed exteriorto another part of the base pipe. The filter mediums may be coupled tothe exterior of the swellable material and supported by part of therigid member at least in a running configuration.

When an activating fluid contacts the screen assemblies 24, 26, theswellable material of each of the screen assemblies can expand.Expansion of the swellable material can displace filter mediums of thescreen assemblies 24, 26 to contact a surface of wellbore 12. Theactivating fluid may be any fluid to which the swellable materialresponds by expanding. Examples of activating fluid include hydrocarbonfluids, water, and gas.

Screen assembly 24 may be a screen assembly that includes filter mediumsthat are laterally and longitudinally adjacent to each other. Screenassemblies 26 may be screen assemblies that include filter mediums thatare only laterally adjacent to each other.

FIGS. 1A and 1B show tubing string 22 with screen assemblies 24, 26.Tubing strings according to various embodiments of the presentinvention, however, may include any number of other tools and systems inaddition to screen assemblies 24, 26. Examples of other tools andsystems include fluid flow control devices, communication systems, andsafety systems. Tubing string 22 may also be divided into intervalsusing zonal isolation devices such as packers. Zonal isolation devicesmay be made from materials that can expand upon contact with a fluid,such hydrocarbon fluids, water, and gas.

In addition, FIGS. 1A and 1B show screen assemblies according to certainembodiments of the present invention in the substantially horizontalsection 18 of the wellbore 12. Various screen assembly embodimentsaccording to the present invention, however, can be used in deviated,vertical, or multilateral wellbores. Deviated wellbores may includedirections different than, or in addition to, a general horizontal or ageneral vertical direction. Multilateral wellbores can include a mainwellbore and one or more branch wellbores. Directional descriptions areused herein to describe the illustrative embodiments but, like theillustrative embodiments, should not be used to limit the presentinvention.

As stated above, certain embodiments of the present invention can bedisposed in an injection well. In an injection well, water or otherfluid is injected into the well to increase flow of hydrocarbon fluidsto a nearby production well. Screen assemblies according to certainembodiments of the present invention can be disposed in the injectionwell to provide support during and after the fluid injection process. Insome embodiments, injected fluid exits a base pipe through openings inthe base pipe, in a rigid member and in a filter medium supported by therigid member. The filter medium may be a support member that does notinclude filtration material, but includes structure capable ofsupporting a formation.

Screen assemblies according to some embodiments of the present inventioncan be disposed in a cased hole completion. In a cased hole completion,a large diameter pipe is positioned between a production string and aformation. The large diameter pipe may be a base pipe with openings in asidewall portion of the base pipe. A screen assembly can be positionedexterior to the large diameter pipe. The screen assembly can include arigid member with an opening that is in fluid communication with anopening in the sidewall portion. A filter medium can be supported by therigid member and can be in fluid communication with the opening in thesidewall portion through the rigid member opening.

FIGS. 2 and 3 show a more detailed view of screen assembly 24 in arunning configuration. The screen assembly 24 depicted in the figuresincludes three rigid members 50, 51, 53 located circumferential to abase pipe 52. The rigid members 50, 51, 53 may be coupled to the basepipe. In other embodiments, a base pipe is provided that includes one ormore rigid members. Screen assemblies according to various embodimentsof the present invention can include any number of rigid members. Forexample, screen assemblies 26 in FIGS. 1A and 1B include two rigidmembers. In other embodiments, screen assemblies include one rigidmember. Rigid members 50, 51, 53 may be constructed from any materialcapable of retaining a general shape upon contact with fluids such ashydrocarbon fluids, gas, and water. Examples of material from whichrigid members 50, 51, 53 can be constructed include metal such as steel.In some embodiments, rigid members 50, 51, 53 are rings constructed fromsteel. The rigid members 50, 51, 53 may include openings that are influid communication with openings in a sidewall of the base pipe 52. Insome embodiments, each of the rigid members 50, 51, 53 includes fouropenings and each of the four openings is in fluid communication withopenings in a sidewall of a base pipe.

Swellable material (not shown) can be disposed circumferential to asecond portion of the base pipe 52 and between the rigid members 50, 51,53. Filter mediums 58 are positioned on an exterior of the swellablematerial and can be supported by rigid members 50, 51, 53 at least in arunning configuration. Each of the filter mediums 58 may be supported byone of the rigid members 50, 51, 53. For example, filter medium 58A issupported by rigid member 50 and filter mediums 58B, 58C is supported byrigid member 51. In some embodiments, each of the filter mediums 58 aresupported by being retained, at least temporarily, by one of the rigidmembers 50, 51, 53. For example, each of the filter mediums 58 can beretained by grooves in one or more rigid members 50, 51, 53 in a runningconfiguration and can be allowed to detach from the grooves in anoperating configuration. In other embodiments, each of the filtermediums 58 are retained by the grooves in one or more rigid members 50,51, 53 in the operating configuration or otherwise supported by acomponent disposed in one of the rigid members 50, 51, 53, such as atelescoping piston.

The filter mediums 58 may be filtration tubes that extend longitudinallyfrom a rigid member and have a substantially rectangular surface shape.In some embodiments, the filter mediums 58 have a surface shape thatresembles, for example, a helicopter blade. Each of the filter mediums58 can include perforations 59 that allow hydrocarbon fluids to enterthe filter mediums 58 for filtration and direction to an inner flow pathof the base pipe 52 through openings in one or more of the rigid members50, 51, 53. In the running configuration shown in FIGS. 2 and 3, thefilter mediums 58 are adjacent to each other. The swellable material canbe configured to expand and displace the filter mediums 58 radiallyduring an operating configuring. In some embodiments, the filter mediums58 are separated by swellable material during the operatingconfiguration.

Filter mediums according to some embodiments of the present inventionmay be or include a control line that can be a fiber optic cable incommunication with a sensor capable of contacting a formation. Thecontrol line can detect conditions associated with the formation andtransmit information about the conditions to the surface for analysis.Filter mediums may also include a fiber optic disposed in housings ofthe filter mediums to provide condition information in a runningconfiguration or otherwise provide information to protect the filtermediums.

FIGS. 4A and 4B show a cross-sectional view of part of the screenassembly 24 from FIGS. 1A (running configuration) and 1B (operatingconfiguration), respectively. FIGS. 4A and 4B show a base pipe 52 thatdefines an internal flow path 54 through which hydrocarbon fluids, forexample, can flow. A swellable material 56 surrounds the base pipe 52.The swellable material 56 can be attached to the base pipe 52, such asby bonding or other suitable technique. Part of a rigid member 50 isshown in FIG. 4A, but it is distant to the cross-section shown in FIG.4A.

Filter mediums are shown as filter mediums 58A-H and are positioned onan exterior of the swellable material 56. FIG. 4A shows eight filtermediums 58A-H, but screen assemblies according to various embodiments ofthe present invention can include any number, from one to many, offilter mediums 58A-H. In some embodiments, the filter mediums 58A-H arebonded to the exterior of swellable material 56. For example, arelatively low swelling or non-swelling material can be positionedbetween the exterior of the swellable material 56 and the filter mediums58A-H. The filter mediums 58A-H can be bonded to the low swelling ornon-swelling material and the low swelling or non-swelling material canbe bonded to the swellable material 56. The low swelling or non-swellingmaterial may assist in preventing the swellable material 56 fromdamaging the filter mediums 58A-H upon expansion.

The swellable material 56 can expand upon contact with an activatingfluid and displace the filter mediums 58A-H to contact a formation 66 atan internal diameter of a wellbore 68. In some embodiments, the filtermediums 58A-H are filtration tubes that can filter particulate materialsfrom hydrocarbon fluids and direct the hydrocarbon fluids to openings inthe base pipe 52. The filter mediums 58A-H illustrated each include ahousing 60 for filter material 62. The filter material 62 can include afiltration opening 64 through which hydrocarbon fluid can be directed toan opening in the base pipe 52. The housing 60 may be made of anysuitable material and may be partially perforated to allow hydrocarbonfluids to enter the housing 60. The filter material 62 may be anysuitable material, such as a fine mesh, that can filter particulatematerials from hydrocarbon fluid.

The filter mediums 58A-H have a kidney-shaped cross-sectional shape. Thekidney-shaped cross-section may assist in attaching the filter mediums58A-H to the swellable material 56 and may result in more surface areaof the filter mediums 58A-H, as compared to filter mediums having adifferent cross-sectional shape, contacting the wellbore 68 uponexpansion of the swellable material 56. Filter mediums according toother embodiments of the present invention, however, may have any typeof cross-sectional shape. Examples of these types of cross-sectionalshapes include an oval, a circle, a rectangle, and a combination of twoor more cross-sectional shapes. The filter mediums 58A-H can have across-sectional length that is selected based on the particularrequirements of a production interval in which the screen assembly 24 islocated.

The swellable material 56 can expand upon contact with an activatingfluid, as shown in FIG. 4B. The activating fluid can include hydrocarbonfluid, water, or gas. Various techniques can be used to contact theswellable material 56 with an activating fluid. One technique includesconfiguring the swellable material 56 to expand upon contact withactivating fluids already present within the wellbore when the screenassembly 24 is installed or with activating fluids produced by theformation 66 after installation. The swellable material 56 may include amechanism for delaying swell to prevent swelling during installation.Examples of a mechanism for delaying swell include an absorptiondelaying layer, coating, membrane, or composition. Another techniqueincludes circulating activating fluid through the well after the screenassembly 24 is installed in the well. In other embodiments, swellablematerial 56 is capable of expansion upon its location in an environmenthaving a temperature or a pressure that is above a pre-selectedthreshold in addition or alternative to an activating fluid.

Expansion of the swellable material 56 can displace the filter mediums58A-H to contact the formation 66 at wellbore 68. The thickness of theswellable material 56 can be optimized based on the diameter of thescreen assembly 24 and the diameter of the wellbore 68 to maximizecontact area of the filter mediums 58A-H with the wellbore 68 uponexpansion. In some embodiments, part of the swellable material 56expands between the filter mediums 58A-H and contacts the formation 66at wellbore 68 between the filter mediums 58A-H to conform tonon-uniform wellbore diameters. The swelled screen assembly 24 canreduce or eliminate annular flow of hydrocarbon and other fluids,provide multiple flow paths for filtered hydrocarbon fluids, and providestabilization to the wellbore 68. For example, the swelled screenassembly 24 can support the formation 66 to prevent formation collapse.In some embodiments, the swelled screen assembly 24 can provide anamount of collapse support within a range of 500 psi to 2000 psi.

Rigid members that support filter mediums according to certainembodiments of the present invention can include pistons disposed inopenings of the rigid members. The pistons may be telescoping pistonsthat can support the filter mediums in a running configuration and anoperating configuration. FIGS. 5A and 5B show a cross-sectional view ofone of the rigid members 50 of the screen assembly 24 from FIGS. 1A(running configuration) and 1B (operating configuration), respectively.The base pipe 52 includes openings 70 in a sidewall portion of the basepipe 52. The rigid member 50 includes openings 72 that are in fluidcommunication with the openings 70 of the base pipe 52. Pistons 74 aredisposed in the openings 72 and can be coupled to filter mediums. FIGS.5A and 5B illustrate a rigid member 50 that can support four filtermediums that are designated 58A, 58C, 58E, and 58G. Rigid membersaccording to various embodiments of the present invention, however, cansupport any number of filter mediums.

The filter mediums 58A, 58C, 58E, 58G can be coupled to a low swellingor non-swelling material 76. The low-swelling or non-swelling material76 may assist the rigid member 50 in supporting the filter mediums 58A,58C; 58E, 58G by providing a temporary seal between the filter mediums58A, 58C, 58E, 58G and rigid member 50. In some embodiments, the lowswelling or non-swelling material 76 is a low swelling or non-swellingrubber.

Pistons 74 may each include a telescoping portion 78 that extendsradially from the openings 72, as shown in FIG. 5B, when the swellablematerial 56 expands to displace the filter mediums 58A, 58C, 58E, 58G tocontact the wellbore 68 at the formation 66. In some embodiments,grooves 80 in the rigid members 50 circumferential to the pistons 74 canreceive O-rings and/or safety catch rings. The O-rings may provide aseal to prevent fluids from traveling between the pistons 74 and therigid member 50. The safety catch rings may prevent the pistons 74 fromexiting the openings 72, such as when the swellable material 56 expands.

FIGS. 5A and 5B show four filter mediums 58A, 58C, 58E, 58G coupled tofour pistons 74. Rigid member 51 from FIGS. 2 and 3 can include asimilar cross-sectional arrangement of the other four filter mediums58B, 58D, 58F, 58H shown in FIGS. 4A and 4B. Rigid member 51 can belocated a selected longitudinal distance from the cross-section shown inFIGS. 5A and 5B. Rigid member 51 may be rotated forty-five degreesrelative to rigid member 50 to allow filter mediums 58A-H to bepositioned adjacent to each other.

FIGS. 6A and 6B illustrate cross-sectional side views of one embodimentof the screen assembly 24 disposed in a wellbore 68 in a runningconfiguration and operating configuration, respectively. The screenassembly includes a base pipe 52 that defines an internal flow path 54through which hydrocarbon fluids can travel. A rigid member 50 isdisposed exterior to a first portion of the base pipe 52. The rigidmember 50 may be a ring made from a metal, composite polymer,non-swelling rubber, or the like. Examples of metals from which therigid member may be made include steel, iron, brass, copper, bronze,tungsten, titanium, cobalt, nickel, and a combination of these and othertypes of materials.

In some embodiments, an interface layer is disposed between the basepipe 52 and at least part of the rigid member 50. The interface layermay bond the rigid member 50 to the base pipe 52. The interface layermay also provide a seal between the rigid member 50 and the base pipe 52to prevent annular flow of fluids from formation 66.

The base pipe 52 includes openings 70 in a sidewall portion of the basepipe 52. The openings 70 are in fluid communication with filter mediums58A, 58E through openings 72 in the rigid member 50. The filter mediums58A, 58E are supported by the rigid member 50 in the runningconfiguration. In each of the openings 72, a piston 74 is disposed. Thepistons 74 allow for fluid communication between the filter mediums 58A,58E and base pipe openings 70.

Swellable material 56 is disposed exterior to a second portion of thebase pipe 52 and longitudinally adjacent to the rigid member 50. Theswellable material 56 is positioned between the base pipe 52 and part ofeach of the filter mediums 58A, 58E. The swellable material 56 canretain an initial size during a running configuration and can expandupon contact with an activating fluid in an operating configuration. Theswellable material 56 can displace the filter mediums 58A, 58E tocontact the wellbore 68 when the swellable material 56 expands in theoperating configuration.

The filter mediums 58A, 58E each include a housing 60 for filtermaterial 62. The housing 60 includes perforations 59 through whichhydrocarbon fluids produced by the formation 66 can flow to the filtermaterial 62. The filter material 62 can filter particulate materialsfrom the hydrocarbon fluids and direct the filtered hydrocarbon fluidsthrough a filtration opening 64 to the flow path 54 through the basepipe openings 70 and rigid member openings 72.

The pistons 74 can support the filter mediums 58A, 58E in the runningconfiguration and the operating configuration. For example, the pistons74 may be coupled to the filter mediums 58A, 58E and the pistons 74 caninclude telescoping portions 78 that can extend radially from the rigidmember openings 72 when the swellable material 56 expands and displacesthe filter mediums 58A, 58E. The rigid member 50 can isolate openingsfrom the swellable material 56 to reduce or eliminate plugging and/orcan allow the screen assembly to be constructed without requiringopenings to be included in the swellable material 56.

Screen assemblies according to certain embodiments of the presentinvention can be constructed using multiple rigid members supportingmultiple filter mediums extending longitudinally along an exterior of abase pipe. FIGS. 7A and 7B show a cross-sectional view of part of ascreen assembly 200 with multiple rigid members in a runningconfiguration and an operating configuration, respectively.

The screen assembly 200 includes a base pipe 202 that has openings 204in a sidewall portion of the base pipe 202. The base pipe 202 can definean internal flow path 203 for hydrocarbon fluids produced by a formation205. A first rigid member 206 is disposed exterior to a firstcircumferential portion of the base pipe 202. A second rigid member 208is disposed exterior to a second circumferential portion of the basepipe 202. Swellable material 210 is disposed exterior to a thirdcircumferential portion of the base pipe 202 between the firstcircumferential portion and the second circumferential portion. Secondswellable material 212 may also be disposed exterior to a fourthcircumferential portion of the base pipe 202 and longitudinally adjacentto the second rigid member 208.

A filter medium 214 is disposed exterior to the swellable material 210and of part of the first and second rigid members 206, 208. The filtermedium 214 can be in fluid communication with the internal flow path 203through two base pipe openings 204 and openings 216 in each of the firstrigid member 206 and the second rigid member 208. The filter medium 214includes a housing 218 with selected perforations 220 that allowhydrocarbon fluid to flow to a filter media 222 disposed within thehousing 218. The filter media 222 can filter particulate materials fromhydrocarbon fluid and direct the filtered hydrocarbon fluid to one orboth openings 216 in the first and second rigid members 206, 208.

A second filter medium 221 is disposed exterior to the second swellablematerial 212 and part of the second rigid member 208. The second filtermedium 220 may be constructed similar to the filter medium 214 and beconfigured to direct filtered hydrocarbon fluid to a second opening 223in second rigid member 208 or to an opening in another rigid member (notshown).

Each of the openings 216 has a piston 224 disposed within it. Each ofthe pistons 224 can be coupled to the filter medium 214 and each of thepistons 224 can include a telescoping portion 226. The second opening223 includes a second piston 228 that is constructed similar to pistons224.

Upon contact with an activating fluid, the swellable material 210 andsecond swellable material 212 can expand radially to displace the filtermedium 214 and second filter medium 220 to contact with the formation205. Examples of the activating fluid include hydrocarbon fluid, water,and gas. The telescoping portion 226 of pistons 224 can extend radiallyfrom openings 216 to provide support to the filter medium 214 during theoperating configuration and provide a conduit through which hydrocarbonfluid can flow from the filter media 222 through openings 216 to theinternal flow path 203. The second piston 228 may perform similarly forthe second filter medium 220 during the operating configuration.

FIGS. 7A and 7B illustrate rigid members located proximate to ends offilter mediums. In other embodiments, rigid members are locatedproximate to other portions of filter mediums. For example, a rigidmember can support a filter medium proximate to a middle of the filtermedium during a running configuration and include openings through whichhydrocarbon fluid can flow from the filter medium to an internal flowpath of a base pipe.

Rigid members according to various embodiments of the present inventioncan be constructed using a variety of designs. FIG. 8 is a side view ofone embodiment of the rigid member 50 from FIGS. 6A-6B. The rigid member50 is a ring that can be located exterior to a portion of a base pipe.The rigid member 50 includes a sloped portion 302, an interveningportion 304, and a filter medium support portion 306. The sloped portion302 has a sloping shape to prevent damage to the remaining portions ofthe rigid member 50 during installation of the rigid member 50 in abore. The intervening portion 304 may connect the sloped portion 302 andthe filter medium support portion 306 and provide stability to the rigidmember 50 to reduce or prevent damage to filter mediums or othercomponents of a screen assembly when installed in the wellbore.

The filter medium support portion 306 can provide support to filtermediums of the screen assembly. The filter medium support portion 306includes receiving portions 308A-C. Each of the receiving portions 308-Cincludes a respective opening 310A-C and each of the receiving portions308A-C can support a respective filter medium. For example, each of thereceiving portions 308A-C may be grooves that can receive a filtermedium in a running configuration and allow the filter medium to detachfrom the grooves during an operating configuration. The openings 310A-Ccan provide fluid communication to an internal flow path of a base pipeand can receive a piston for supporting the filter mediums during therunning configuration and an operating configuration.

The receiving portions 308A-C can be staggered to support overlap offilter mediums and to define grooves. For example, FIG. 8 shows onereceiving portion 308B having a different length than the otherreceiving portions 308A, 308C. FIG. 9 is a cross-sectional view of rigidmember 300 along line 9-9. Openings 310A-D are shown in FIG. 9 asdefined by grooves in filter medium support portion 306. A filter mediumcan be positioned over 310A and coupled to a piston disposed in opening310A. Similarly, each of openings 310B-D can be associated with arespective filter medium.

The rigid member 50 may be made from a metal, composite polymer,non-swelling rubber, or the like. Examples of metals from which therigid member 50 may be made include steel, iron, brass, copper, bronze,tungsten, titanium, cobalt, nickel, and a combination of these or othertypes of materials.

Screen assemblies according to some embodiments of the present inventioncan include multiple rigid members. For example, rigid member 50 can belocated exterior to a first portion of a base pipe and a second rigidmember can be located exterior to a second portion of the base pipe.Filter mediums can be located between the two rigid members. In someembodiments, rigid member 50 can support four filter mediums and thesecond rigid member can support four different filter mediums. FIG. 2shows an example of a similar arrangement. The second rigid member canbe rotated, for example by forty-five degrees relative to the rigidmember 50, to align a receiving portion of the rigid member 50 that witha non-receiving portion of the second rigid member that has a greatercross-sectional radius. In this configuration, the filter mediumsassociated with the rigid member 50 and filter mediums associated withthe second rigid member can be positioned adjacent to each other in analternating arrangement.

Illustrative Swellable Material Compositions

Swellable material according to certain embodiments can be formed fromone or more materials that swell upon contact with an activating fluid.For example, the swellable material may be a polymer that is capable ofswelling to a size that is multiple times its initial size upon contactwith an activating fluid that stimulates the material to expand. In someembodiments, the swellable material swells upon contact with anactivating fluid that is a hydrocarbon fluid or a gas. The hydrocarbonfluid is absorbed by the swellable material and the absorption causesthe volume of the swellable material to increase, thereby expandingradially. The swellable material may expand the filter mediums and partof the outer surface of the swellable material contacts a formation facein an open hole completion or a casing wall in a cased wellbore.

Some embodiments of the swellable material may be made from an elasticpolymer. Examples of elastic polymers include ethylene propylene dienemonomer (EPDM) rubber, styrene butadiene, natural rubber, ethylenepropylene monomer rubber, ethylene vinyl acetate rubber, hydrogenizedacrylonitrile butadiene rubber, acylonitrile butadiene rubber, isoprenerubber, chloroprene rubber and polynorbornene. The swellable materialmay also include other materials dissolved in, or in mechanical mixture,with the other materials that form the swellable material. Examples ofother materials include fibers of cellulose, polyvinyl chloride, methylmethacrylate, acrylonitrile, ethylacetate, or other polymers.

In some embodiments, the swellable material is configured to expand uponcontact with an activating fluid that is water. For example, theswellable material may be a water-swellable polymer such as awater-swellable elastomer or water-swellable rubber. More specifically,the swellable material may be a water-swellable hydrophobic polymer orwater-swellable hydrophobic copolymer such as a water-swellablehydrophobic porous copolymer. Other polymers that can be used to formthe swellable material include hydrophilic monomers and hydrophobicallymodified hydrophilic monomers. Examples of suitable hydrophilic monomersinclude acrylamide, 2-acrylamido-2methyl propane sulfonic acid,N,N-dimethylacrylamide, vinyl pyrrolidone, dimethylaminoethy1methacrylate, acrylic acid, trimethylammoniumethyl, methacrylatechloride, dimethylaminopropylmethacrylamide, methacrylamide, andhydroxyethyl acylate.

A variety of hydrophobically modified hydrophilic monomers can beutilized in accordance with certain embodiments. Examples ofhydrophobically modified hydrophilic monomers include alkyl acrylates,alkyl methacrylates, alkyl acrylamides, alkyl methacrylamides (wherealkyl radicals have from about 4 to about 22 carbon atoms), alkyldimethylammoniumethyl methacrylate chloride and alkyldimethylammoniumethyl methacrylate iodide (where the alkyl radicals havefrom about 4 to about 22 carbon atoms), alkyldimethylammonium-propylmethacrylamide bromide, alkyl dimethylammoniumpropylmethacrylamide chloride and alkyldimethylammonium-propylmethacrylamide iodide (where the alkyl groupshave from about 4 to about 22 carbon atoms).

Polymers suitable in swellable material according to certain embodimentscan be prepared by polymerizing any one or more of the hydrophilicmonomers with any one or more of the hydrophobically modifiedhydrophilic monomers. The polymerization reaction can be formed invarious ways, an example of which is described in U.S. Pat. No.6,476,169, which is incorporated herein by reference. These polymers mayhave estimated molecular weights in the range from about 100,000 toabout 10,000,000, with a preferred range of 250,000 to about 3,000,000.These polymers may also have mole ratios of the hydrophilic monomer(s)to the hydrophobically modified hydrophilic monomer(s) in the range offrom about 99.98:0.02 to about 90:10.

In some embodiments, the swellable material may be made from a saltpolymer such as polyacrylamide or modified crosslinkedpoly(meth)acrylate that tends to attract water from salt water throughosmosis. For example, when water that flows from an area of low saltconcentration (the formation water) to an area of high saltconcentration (a salt polymer), across a semi-permeable membrane (aninterface between the salt polymer and production fluids), the saltpolymer allows water molecules to pass, but prevents passage ofdissolved salts.

The foregoing description of the embodiments, including illustratedembodiments, of the invention has been presented only for the purpose ofillustration and description and is not intended to be exhaustive or tolimit the invention to the precise forms disclosed. Numerousmodifications, adaptations, and uses thereof will be apparent to thoseskilled in the art without departing from the scope of this invention.

1. A screen assembly capable of being disposed in a bore, the screenassembly comprising: a base pipe comprising a sidewall portion having anopening therein; a rigid member disposed exterior to a first portion ofthe base pipe, the rigid member comprising an opening in fluidcommunication with the opening of the base pipe; a swellable materialdisposed exterior to a second portion of the base pipe; and a filtermedium at least partially disposed exterior to the swellable material,the filter medium being in fluid communication with the opening of therigid member, wherein, in response to contact with an activating fluid,the swellable material is capable of expanding and displacing at leastpart of the filter medium toward a surface of the bore.
 2. The screenassembly of claim 1, further comprising: a piston disposed in theopening of the rigid member and coupled to the base pipe, wherein thepiston comprises a telescoping portion coupled to the filter medium, theradially telescoping portion being capable of extending from the openingof the rigid member when the swellable material expands, wherein thefilter medium is capable of filtering fluids and directing the fluids toan internal flow path of the base pipe through the piston.
 3. The screenassembly of claim 1, further comprising a material between the filtermedium and the rigid member, the material comprising at least one of anon-swelling media or a low-swelling media and the material beingcapable of providing a temporary seal between the filter medium and therigid member.
 4. The screen assembly of claim 3, wherein the materialcomprises rubber.
 5. The screen assembly of claim 1, wherein theactivating fluid is at least one of a hydrocarbon fluid, water, or agas.
 6. The screen assembly of claim 1, wherein the filter medium has across-sectional shape of at least one of: a kidney shape; an oval; acircle; or a rectangle.
 7. The screen assembly of claim 1, wherein therigid member is a ring that is at least one of: a metal; a compositepolymer; or a non-swelling rubber compound.
 8. A screen assembly capableof being disposed in a bore, the screen assembly comprising: a base pipecomprising a sidewall portion having a plurality of openings therein; arigid member disposed exterior to a first portion of the base pipe, therigid member comprising a plurality of openings, each opening of theplurality of openings of the rigid member being in fluid communicationwith an opening of the plurality of openings of the sidewall portion; aswellable material disposed exterior to a second portion of the basepipe; and a plurality of filter mediums at least partially disposedexterior to the swellable material, each of the plurality of filtermediums being in fluid communication with at least one of the pluralityof openings of the rigid member, wherein, in response to contact with anactivating fluid, the swellable material is capable of expanding anddisplacing at least part of each of the plurality of filter mediumstoward a surface of the bore.
 9. The screen assembly of claim 8, furthercomprising: a plurality of pistons comprising a telescoping portion, theplurality of pistons being coupled to the base pipe, wherein eachopening of the plurality of openings of the rigid member has a piston ofthe plurality of pistons disposed therein, the telescoping portion beingcapable of extending from the rigid member when the swellable materialexpands.
 10. The screen assembly of claim 8, wherein the activatingfluid is at least one of a hydrocarbon fluid, water, or a gas.
 11. Thescreen assembly of claim 8, wherein each filter medium of the pluralityof filter mediums has a cross-sectional shape of at least one of: akidney shape; an oval; a circle; or a rectangle.
 12. The screen assemblyof claim 8, wherein the rigid member is a ring that is at least one of:a metal; a composite polymer; or a non-swelling rubber compound.
 13. Ascreen assembly capable of being disposed in a bore, the screen assemblycomprising: a base pipe comprising a sidewall portion having a firstplurality of openings and a second plurality of openings therein, thefirst plurality of openings being at a first portion of the base pipe,the second plurality of openings being at a second portion of the basepipe; a first rigid member disposed exterior to the first portion of thebase pipe; a second rigid member disposed exterior to the second portionof the base pipe; a swellable material disposed exterior to a thirdportion of the base pipe; and a plurality of filter mediums at leastpartially disposed exterior to the swellable material, each of theplurality of filter mediums being in fluid communication with at leastone opening of the first plurality of openings or the second pluralityof openings, wherein, in response to contact with an activating fluid,the swellable material is capable of expanding and displacing at leastpart of each of the plurality of filter mediums toward a surface of thebore.
 14. The screen assembly of 13, wherein the third portion of thebase pipe is located between the first portion of the base pipe and thesecond portion of the base pipe.
 15. The screen assembly of claim 13,wherein each of the plurality of filter mediums is in fluidcommunication with at least one opening of the first plurality ofopenings or the second plurality of openings through at least one of aplurality of openings of the first rigid member or a plurality ofopenings of the second rigid member.
 16. The screen assembly of 13,wherein each of the first rigid member and the second rigid membercomprise: a first receiving portion for supporting a first filter mediumof the plurality of filter mediums in a running configuration; and asecond receiving portion for supporting a second filter medium of theplurality of filter mediums in the running configuration.
 17. The screenassembly of 16, wherein the first receiving portion and the secondreceiving portion define grooves for supporting the first filter mediumand the second filter medium of the plurality of filter mediums in therunning configuration.
 18. The screen assembly of claim 17, wherein thesecond rigid member is rotated forty-five degrees relative to the firstrigid member, wherein the first receiving portion of the first rigidmember is aligned with the second receiving portion of the second rigidmember.
 19. The screen assembly of claim 13, wherein the activatingfluid is at least one of a hydrocarbon fluid, water, or a gas.
 20. Thescreen assembly of claim 13, wherein each of the plurality of filtermediums has a cross-sectional shape of at least one of: a kidney shape;an oval; a circle; or a rectangle.
 21. The screen assembly of claim 13,wherein each of the first rigid member and the second rigid member is aring that is at least one of: a metal; a composite polymer; or anon-swelling rubber compound.